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Abstract:

The present invention relates to a photobioreactor, and more
particularly, a photobioreactor for culturing living organisms such as
microalgae, which carry out photosynthesis using carbon dioxide and light
energy. The photobioreactor includes: (a) a reaction vessel, in which
photosynthesis occurs by photosynthetic organisms; (b) a multipurpose
inlet/outlet formed at the outside upper end of the reaction vessel; (c)
an outer pipe connected to the multipurpose inlet/outlet at the outside
of the reaction vessel; and (d) an inner pipe connected to the
multipurpose inlet/outlet at the inside of the reaction vessel, wherein
the reaction vessel is made of a transparent film.
The photobioreactor according to the present invention is advantageous in
that the reaction vessel in which photosynthesis occurs is a plate-type
and made of a transparent film, thus achieving improved light
transmittance and mobility, and enabling the economically advantageous
manufacture and operation thereof. Therefore, the photobioreactor of the
present invention can be easily installed anywhere carbon dioxide is
discharged, such as around a power-generating plant, in an urban region,
a farm, etc., to culture a variety of photosynthetic organisms, and thus
to produce useful substances having economically high added values.

Claims:

1. A photobioreactor, comprising: (a) a reaction vessel in which
photosynthesis occurs by photosynthetic organisms; (b) a multipurpose
inlet/outlet formed at the outside upper end of the reaction vessel; (c)
an outer pipe connected to the multipurpose inlet/outlet at the outside
of the reaction vessel; and (d) an inner pipe connected to the
multipurpose inlet/outlet at the inside of the reaction vessel; wherein,
the reaction vessel is made of a transparent film.

2. The photobioreactor of claim 1, wherein the reaction vessel includes,
at the upper portion thereof, a hanging portion hanging the
photobioreactor.

4. The photobioreactor of claim 1, wherein the multipurpose inlet/outlet
includes a hole for carrying out a function selected from the group
consisting of (a) injecting photosynthetic organisms and culture
solution, (b) injecting a carbon dioxide-containing gas, (c) extracting a
specimen sample, and (d) discharging gas.

5. The photobioreactor of claim 4, wherein the outer pipe outside the
reaction vessel is connected to the inner pipe inside the reaction vessel
through the hole formed in the multipurpose inlet/outlet.

6. The photobioreactor of claim 1, wherein a sprayer for dispersing
carbon dioxide in the photobioreactor is attached to the end of the inner
pipe for injecting a carbon-containing gas among the inner pipes.

7. The photobioreactor of claim 6, wherein the lower portion of the
reaction vessel where the sprayer is located includes a groove in a "V"
shape.

8. The photobioreactor of claim 7, wherein the groove in a "V" shape has
an internal angle from 30 to 160.degree..

9. The photobioreactor of claim 7, wherein the number of grooves in a "V"
shape has the same as the number of sprayers.

10. The photobioreactor of claim 1, wherein the inner space of the
reaction vessel is partially partitioned.

11. The photobioreactor of claim 10, wherein the inner space of the
reaction vessel is partially partitioned by attaching predetermined
portions inside the front and rear surfaces of the reaction vessel to
each other in a vertical line shape to form a corrugated partition.

12. The photobioreactor of claim 11, wherein the corrugated partition is
formed between the multipurpose inlet/outlet and the bottom of the
reaction vessel.

13. A photobioreactor, comprising: (a) a reaction vessel made of a
transparent film, in which photosynthesis occurs by photosynthetic
organisms; (b) a multipurpose inlet/outlet formed at the outside upper
end of the reaction vessel; (c) an outer pipe connected to the
multipurpose inlet/outlet at the outside of the reaction vessel; and (d)
an inner pipe connected to the multipurpose inlet/outlet at the inside of
the reaction vessel; wherein the inner space of the reaction vessel is
partially partitioned.

14. The photobioreactor of claim 13, wherein the inner space of the
reaction vessel is partially partitioned by attaching predetermined
portions inside the front and rear surfaces of the reaction vessel to
each other in a vertical line shape to form a corrugated partition.

15. The photobioreactor of claim 14, wherein the corrugated partition is
formed between the multipurpose inlet/outlet and the bottom of the
reaction vessel.

Description:

TECHNICAL FIELD

[0001] The present invention relates to a photobioreactor, and more
particularly, to a photobioreactor for culturing living organisms such as
microalgae, which carry out photosynthesis using carbon dioxide and light
energy.

BACKGROUND ART

[0002] Greenhouse gas has been emitted by the use of fossil fuel, thus
causing global warming. Such global warming results in climate change and
environmental change, and jeopardizes the survival of all organisms
including humans. Therefore, many studies and developments for reducing
carbon dioxide have been performed. As one method, a study has been
conducted actively for recovery and biological conversion of carbon
dioxide.

[0003] A study has been conducted actively for microalgae as
photosynthetic organisms for the biological conversion of carbon dioxide.
Phytoplankton microalgae use the sun as energy source, similarly to other
photosynthetic organisms, and grow through photosynthesis for
immobilizing carbon dioxide.

[0004] The reasons why microalgae draw attention as means for immobilizing
carbon dioxide are as follows. First, since microalgae harness solar
energy as a main energy source, similarly to carbon dioxide absorption in
a plant, microalgae need only a small amount of energy for recovering
carbon dioxide. Therefore, since the small amount of carbon dioxide is
produced at the time of operation of immobilizing carbon dioxide, removal
efficiency is high from the viewpoint of a carbon dioxide resin.

[0005] Second, microalgae have the immobilization rate of carbon dioxide
higher than that of a plant, and a required site area is small. According
to the findings of the Tokyo Electric Power Research Institute, the
immobilization rate of microalgae is 2.8 times higher than the fastest
growing sugar cane, and 15 times higher than of the most common species
of pine in Korea.

[0006] In addition, there is no need for separation and concentration of
carbon dioxide because carbon dioxide can be immobilized directly from
combustion gas. In addition, microalgae which are produced during
immobilization of carbon dioxide may be used as biological products
because they contain various useful substances.

[0007] However, when the carbon dioxide-immobilization process using
microalgae is performed by using the bioreactor which has been applied
practically in industries, it is difficult to reduce energy and supply
light energy for allowing microalgae to grow, due to high consumption of
electrical energy.

[0008] Generally, an apparatus for culturing photosynthetic organisms for
the purpose of carbon dioxide immobilization is usually divided into an
open-type culture apparatus for outdoor mass culture and a close-type
photobioreactor having a small volume. In the case of the open-type
outdoor culture apparatus, it was usually used in a form such as a lake
or a large pond in Germany, Japan or US. However, since the open-type
outdoor mass culture apparatus in a form of a pond should be manufactured
by an expensive reinforced concrete structure, a lot of energy is
consumed at the time of consecutive stirring, and pollution prevention,
and separation and purification of cultured microalgae are difficult.
Furthermore, in the case of the mass culture apparatus, it has slow
growth rate of photosynthetic organisms and low growth yield because
generally light is not effectively transferred to the inner portion.

[0009] Presently, the developed close-type photobioreactor includes a
general stirring type reactor, a plate-type reactor, a tube-type reactor,
and a column-type reactor, and the like. It could be expected that the
close-type reactor has a cell growth rate higher than that of the outdoor
mass culture apparatus, and it is easy to control operation conditions.
However, the close-type reactor has a high initial cost and a high
operation management cost, and it is difficult to use efficiently light
energy as a crucial factor of a photobioreactor. In order to use light
energy, a reactor in which a light source is installed in the reactor was
developed. However, the reactor has good light efficiency, but it is not
efficient because electrical energy of artificial fluorescent lamp or LED
is used. In addition, since the close-type reactor is generally
manufactured by a reinforced glass or acryl which is stationary, it is
difficult to perform mass culture and clean the reactor, and indoor space
cannot be employed effectively.

[0010] The present inventors found that, when a reaction vessel where
photosynthesis occurs is made of a transparent film, instead of a
reinforced glass or acryl that has been generally used, the reaction
vessel has good light transmittance, thus enabling microalgae to grow
well, and the reaction vessel has good mobility because it is light, thus
enabling the economically advantageous manufacture and operation thereof.
Also, the present inventors found that, when the inner space of a
photobioreactor made of a transparent film is partially partitioned,
carbon dioxide and photosynthetic organisms are further dispersed therein
and reduction of light transmittance caused by the deformation of the
reactor may be prevented. The present invention was accomplished.

DISCLOSURE OF INVENTION

Technical Problem

[0011] An object of the present invention is to provide an economical
photobioreactor which has low consumption of energy and has a structure
capable of obtaining sufficient light energy at the time of operation of
the reactor, compared to a bioreactor such as a stirring type reactor or
a plate-type reactor, which has been widely spread.

[0012] Another object of the present invention is to provide a
photobioreactor capable of a simplified manufacture and operation, and
good mobility.

Technical Solution

[0013] The photobioreactor according to the present invention is
advantageous in that the reaction vessel in which photosynthesis occurs
is a plate-type and made of a transparent film, thus achieving improved
light transmittance and mobility, and enabling the economically
advantageous manufacture and operation thereof. The photobioreactor does
not have the flat bottom portion thereof, but has a structure in which
the grooves in the "V" shape are consecutively formed. Therefore, culture
solution may be mixed by gas such as carbon dioxide or gas without a
stirrer such as a magnetic bar, an impeller, or the like.

[0014] Since the inner space of the reactor is partially partitioned,
carbon dioxide and photosynthetic organisms may be further dispersed
therein and reduction of light transmittance caused by deformation of the
reactor may be prevented. Therefore, the photobioreactor of the present
invention can be easily installed anywhere carbon dioxide is discharged,
such as around a power-generating plant, in an urban region, a farm,
etc., to culture a variety of photosynthetic organisms, thereby making it
possible to produce useful substances having economically high added
value.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 shows the structure of a photobioreactor according to an
exemplary embodiment of the present invention;

[0016]FIG. 2 illustrates a combination of a fixing connection portion of
a multipurpose inlet/outlet according to an exemplary embodiment of the
present invention;

[0017] FIG. 3 shows a combination example of a multipurpose inlet/outlet
according to an exemplary embodiment of the present invention;

[0018] FIG. 4 shows a multipurpose inlet/outlet formed in a
photobioreactor according to an exemplary embodiment of the present
invention;

[0019] FIG. 5 shows the structure of a photobioreactor in which the inner
space is partially partitioned according to an exemplary embodiment of
the present invention;

[0020] FIG. 6 is a photograph showing one example of a photobioreactor
according to an exemplary embodiment of the present invention;

[0021] FIG. 7 is a photograph showing one example of a photobioreactor
according to an exemplary embodiment of the present invention;

[0022] FIG. 8 is a graph showing a relationship between an inner distance
(side surface length) of a reactor and a light flux, in accordance with
materials of a photobioreactor according to an exemplary embodiment of
the present invention;

[0023] FIG. 9 is a graph showing the amount of astaxanthin to be produced
in a photobioreactor according to an exemplary embodiment of the present
invention and a general cylindrical stirring type reactor;

[0024]FIG. 10 is a graph showing the result of chlorella culture in a
photobioreactor according to an exemplary embodiment of the present
invention and an Erlenmeyer flask;

[0025] FIG. 11 is a graph measuring light transmittance in accordance with
the depth of a photobioreactor according to an exemplary embodiment of
the present invention; and

[0026] FIG. 12 is a graph showing a relationship between an inner distance
(side surface length) of a reactor and a light flux, in accordance with
materials of a photobioreactor according to an exemplary embodiment of
the present invention and materials of a general cylindrical stirring
type reactor.

[0050] The present invention is to confirm that even though a plate-type
photobioreactor is manufactured by using a reaction vessel in which
photosynthesis occurs, made of a transparent film instead of a reinforced
glass or acryl that has been used generally, the photobioreactor has good
light transmittance.

[0051] In the present invention, a photobioreactor including a plate-type
reaction vessel which is made of a transparent film was subjected to
culturing microalgae. As a result, it was confirmed that the
photobioreactor has good light transmittance.

[0052] In other words, in an exemplary embodiment of the present
invention, a plate-type photobioreactor which includes a reaction vessel
made of a low density polyethylene (LDPE) film, and a mixed film
(PET+CPP) of polyethylene terephthalate and non-stretched polypropylene
is manufactured, and then Haematococcus pluvialis microalgae is cultured.
As a result, it could be confirmed that the plate-type photobioreactor
has good light transmittance, in which microalgae grow well.

[0053] Therefore, in one aspect of the present invention, there is
provided a photobioreactor, including: (a) a reaction vessel, in which
photosynthesis occurs by photosynthetic organisms; (b) a multipurpose
inlet/outlet formed at the outside upper end of the reaction vessel; (c)
an outer pipe connected to the multipurpose inlet/outlet at the outside
of the reaction vessel; and (d) an inner pipe connected to the
multipurpose inlet/outlet at the inside of the reaction vessel, wherein
the reaction vessel is made of a transparent film.

[0054] Hereinafter, a photobioreactor according to the present invention
will be described with reference to the drawings.

[0055] FIG. 1 shows the structure of a photobioreactor 100 according to an
exemplary embodiment of the present invention.

[0056] As shown in FIG. 1, the reaction vessel 10 is made of a transparent
film, and includes, at the upper portion thereof, a hanging portion 60 so
as to support or fix the reaction vessel. The hanging portion 60 is
hollow such that a support bar 70 may be inserted thereinto. The support
bar 70 is provided to support the photobioreactor, and it is not
specifically limited as long as the photobioreactor has strength that may
support a weight of the photobioreactor. Both ends of the support bar 70
may be hung by a separate stand or the like.

[0057] The transparent film is not specifically limited as long as it is
transparent and has good light transmittance such that photosynthetic
organisms may grow easily. The transparent film includes (a) low density
polyethylene (LDPE), (b) a mixed film of polyethylene terephthalate and
non-stretched polypropylene (PET+CPP), (c) polyacetal (POM), (d)
polycarbonate (PC), (e) polyester sulfone (PES), (f) polyethylene (PE),
(g) polyvinyl chloride (PVC), (h) polyethylene terephthalate (PET), (i)
polypropylene (PP), and (j) polyphenylene oxide (PPO=PPE). The
transparent film is light and transparent, and has good mechanical
strength, as well as the same light transmittance, compared to glass or
acryl that has been widely used for a reaction vessel of a
photobioreactor.

[0058] The reaction vessel 10 constituting the photobioreactor according
to the present invention may be a plate-type and a bubble column-type
when culture solution is injected. Since the reaction vessel is a
plate-type, it has good light transmittance because of a small distance
of transmitted light in the reactor.

[0059] The multipurpose inlet/outlet 20 is attached detachably at the
outside upper end of the reaction vessel 10. FIG. 2 illustrates a
combination of a fixing connection portion of a multipurpose inlet/outlet
according to an exemplary embodiment of the present invention. As shown
in FIG. 2, the fixing connection portion 24 disposed inside and outside
the reaction vessel 10 includes a nut type circular fixing pin 21
disposed outside the reaction vessel and a bolt type circular fixing pin
23 disposed inside the reaction vessel.

[0060] FIG. 3 shows a combination example of a multipurpose inlet/outlet
according to an exemplary embodiment of the present invention. As shown
in FIG. 3, a fixing connection portion cap 26 and the fixing connection
portion 24 may be combined with each other using bolt type and nut type
screws. At the time of combining the fixing connection portion cap 26 and
fixing connection portion 24 with each other, a stopping rubber 25 may be
combined therebetween for prevention of pollution by outer microorganisms
or organisms. The stopping rubber may include holes such that an outer
pipe and an inner pipe may be inserted thereinto.

[0061] The multipurpose inlet/outlet 20 includes a hole for carrying out a
function selected from the group consisting of (a) injecting a
photosynthetic organisms and culture solution, (b) injecting a carbon
dioxide-containing gas, (c) extracting a specimen sample and (d)
discharging gas. The number of holes is not specifically limited.

[0062] FIG. 4 shows a multipurpose inlet/outlet formed in a
photobioreactor according to an exemplary embodiment of the present
invention. As shown in FIG. 4, the stopping rubber 25 of the multipurpose
inlet/outlet 20 may include an injection hole 32 of photosynthetic
organisms and culture solution, an injection hole 34 of a carbon
dioxide-containing gas, an extraction hole 36 of a specimen sample, or a
discharge hole 38 for gas.

[0063] The holes are formed in the multipurpose inlet/outlet 20 such that
outer pipes 42, 44, 46 and 48 disposed outside the reaction vessel may be
connected to inner pipes 42, 44', 46' and 48' disposed inside the
reaction vessel, respectively. More specifically, the outer pipe includes
an outer pipe 42 for injecting photosynthetic organisms and culture
solution, an outer pipe 44 for injecting a carbon dioxide-containing gas,
an outer pipe 46 for extracting a specimen sample and an outer pipe 48
for discharging gas. The inner pipe includes an inner pipe 42' for
forming an injection hole for injecting photosynthetic organisms and
culture solution, an inner pipe 44' for injecting a carbon
dioxide-containing gas, an inner pipe 46' for extracting a specimen
sample and an inner pipe 48' for discharging gas.

[0064] The outer pipe and inner pipe are not specifically limited as long
as they may have a hole in a hose shape, and include a stainless steel
hose or a silicon hose, which is sterilizable. In addition, the outer
pipe and the inner pipe are integrally formed therewith or may be
connected to the multipurpose inlet/outlet 20, respectively.

[0065] The outer pipe 48 for discharging gas which is connected to the
discharge hole 38 for gas is allowed to discharge gas and unabsorbable
carbon dioxide to the outside of the reactor. The outer pipe 46 for
extracting a specimen sample which is connected to the extraction hole 36
of the specimen sample is allowed to extract a specimen at the time of
operation of the photobioreactor 100. At the time of extracting the
specimen sample, the outer pipe 46 for the extraction may further include
a close valve (not shown) such that pollution substances are not
introduced into the reactor.

[0066] The outer pipe 44 for injecting carbon dioxide-containing gas which
is connected to the injection hole 34 for gas including carbon
dioxide-containing gas is allowed to supply carbon dioxide to the
photobioreactor 100. Then, a feed rate of carbon dioxide may be
controlled through a flow meter that is separately provided outside the
photobioreactor. A carbon dioxide distribution may be varied depending on
a size or properties of the photosynthesis organisms, internal size of
the reactor, and properties of a sprayer, in the photobioreactor 100.
Thus, a feed rate of carbon dioxide may be controlled using the flow
meter.

[0067] The number of multipurpose inlets/outlets 20 installed may depend
on the volume of the photobioreactor 100.

[0068] A sprayer 50 for dispersing carbon dioxide in the photobioreactor
is attached to the end of the inner pipe 44' for injecting the carbon
dioxide-containing gas in the inner pipe. The sprayer 50 serves to help
to disperse photosynthesis organisms in the reactor.

[0069] The sprayer 50 is not limited to a cylindrical type, a polygonal
type, or a spherical type as long as it enables air to be injected.

[0070] Furthermore, in the present invention, when the lower portion of
the reactor is manufactured to have corrugation instead of a flat
surface, it was expected that a space (i.e., dead zone) where cells are
not mixed by gravity and accumulated space (dead zone) is reduced, and
thus the culture solution may be mixed easily.

[0071] In another exemplary embodiment of the present invention, as shown
in FIG. 1, the reaction vessel is manufactured such that the lower
portion thereof where a sprayer is located includes a groove in a "V"
shape, in which microalgae Haematococcus pluvialis are cultured.
Therefore, it could be confirmed that culture solution is mixed
homogenously without a stirrer.

[0072] Therefore, the reaction vessel is manufactured such that the lower
portion where the sprayer is located includes a groove in a "V" shape.
The groove in a "V" shape may be formed such that the number of grooves
in the "V" shape is the same as the number of sprayers. The number of
sprayers or the number of grooves in the "V" shape may be selected
optionally, i.e., 1 to 100, and preferably 1 to 10.

[0073] The groove in the "V" shape has an internal angle of 30 to
160°. When the internal angle of the groove in the "V" shape is
less than 30°, the interval of the partition portion of the
reactor is reduced, or the groove portion in the "V" shape is increased
significantly. When the internal angle of the groove in the "V" shape is
larger than 160°, the groove in the "V" shape may not be formed.
The maximum internal interval of the groove in the "V" shape may be
suitably selected, without limitation, depending on the volume of the
reactor, the diameter of a carbon dioxide sprayer to be used, or the
like. For example, when a carbon dioxide sprayer having a diameter of 1.2
cm is used in the reactor having a volume of 3 to 8 L, the groove in the
"V" shape may have the maximum internal interval of 3 to 30 cm. When the
volume of the reactor or the size of a carbon dioxide sprayer is
increased, the maximum internal interval of the groove in the "V" shape
may be also increased.

[0074] The photobioreactor 100 according to the present invention has a
structure such that the lower portion of the reaction vessel 10 where the
sprayer 50 is located includes a groove in the "V" shape, and
photosynthetic organisms are collected at the edge of the groove in the
"V" shape, and therefore culture solution may be mixed by gas such as
carbon dioxide or gas without a stirrer such as a magnetic bar, an
impeller, or the like.

[0075] The photobioreactor 100 according to the present invention has a
height of 20 to 500 cm, and preferably 40 to 200 cm, a width length of 3
to 1500 cm, and a side surface length (i.e., a depth of reactor) of 2 to
15 cm. The term "side surface length" means a depth when culture solution
is injected to the photobioreactor.

[0076] On the other hand, the present inventors found that a plate-type
photobioreactor is manufactured using a reaction vessel where
photosynthesis occurs, made of a transparent film, instead of a
reinforced glass, or acryl that has been used generally. Herein, when the
inner space of a photobioreactor is partially partitioned, carbon dioxide
and photosynthetic organisms are further dispersed therein and reduction
of light transmittance caused by the deformation of the reactor may be
prevented.

[0077] In the present invention, the photobioreactor including a reaction
vessel, made of a transparent film, in which the inner space is partially
partitioned, was subjected to culturing microalgae. As a result, it was
confirmed that the photobioreactor has good light transmittance.

[0078] Therefore, in another aspect of the present invention, there is
provided a photobioreactor, including: (a) a reaction vessel made of a
transparent film, in which photosynthesis occurs by photosynthetic
organisms; (b) a multipurpose inlet/outlet formed at the outside upper
end of the reaction vessel; (c) an outer pipe connected to the
multipurpose inlet/outlet at the outside of the reaction vessel; and (d)
an inner pipe connected to the multipurpose inlet/outlet at the inside of
the reaction vessel, wherein the inner space of the reaction vessel is
partially partitioned.

[0079] FIGS. 5 to 7 show the structure of a photobioreactor 200 in which
the inner space is partially partitioned according to an exemplary
embodiment of the present invention.

[0080] As shown in FIG. 5, the inner space of the reaction vessel 10 is
partially partitioned by attaching predetermined portions inside the
front and rear surfaces of the reaction vessel to each other in a
vertical line shape to form a corrugated partition 80. Since the reaction
vessel 10 is made of a transparent film, when the predetermined portions
inside the reaction vessel are attached to each other in a vertical line
shape, the inner space may be partitioned.

[0081] In the present invention, the inner space was partially
partitioned. It means that the inner space of the reaction vessel is
partitioned in a vertical line shape, the inner space was not partitioned
from the top to the bottom of the reaction vessel, but a certain interval
is spaced apart from both the top and the bottom, and the inner space was
partitioned. Therefore, culture solution in the reaction vessel may be
transferred through a path spaced apart by a certain interval.

[0082] The corrugated partition may be formed between the multipurpose
inlet/outlet and the bottom of the reaction vessel. The length of the
corrugated partition may be varied depending on the height of the
reactor. When the length of the corrugated partition, that is, the
surface where the front surface of the reaction vessel is attached to the
inside of the rear surface thereof is too short, a partition effect
cannot be obtained. When the length is too long, carbon dioxide and
photosynthetic organisms in the inner space of the reactor may hardly
obtain homogeneous distribution.

[0083] The interval of the partition, that is, a distance between
corrugated partition and subsequent corrugated partition may be selected
suitably without limitation depending on the volume of the reactor, or
the diameter of a carbon dioxide sprayer to be used, as described above.

[0084] As described above, the photobioreactor where the inner space is
partially partitioned is formed such that the lower portion of the
reaction vessel where a sprayer is located includes a groove in the "V"
shape.

EXAMPLES

[0085] Hereinafter, the present invention will be described in detail with
reference to the Examples. The Examples include one example of the
present invention, and are not to be construed as limiting a scope of the
present invention, which is evident to those skilled in the art.

[0086] Particularly, the Examples were subjected to culturing Chlorella
vulgaris and Haematococcus pluvialis among microalgae in the
photobioreactor according to the present invention. However, it is
evident to those skilled in the art that other microalgae are allowed to
be cultured.

Example 1

Measure of Light Transmittance in Photobioreactor Made of Transparent Film

[0088] In the manufactured photobioreactor, Haematococcus pluvialis
(NIES-144) provided from MCC-NIES (Microbial Culture Collection, National
Institute of Environmental Studies (NIES), Japan) was cultured under
conditions (culture temperature: 23-25, culture time: 150 hours, pH: 7.5)
at a concentration of 0.33 g/L in the NIES medium in which a carbon
source is removed (NIES-C). During the culture, distance was measured in
accordance with a light flux (360 μmol photon m-2s-1) with
the same intensity. A result was shown in FIG. 8.

[0089] As shown in FIG. 8, the photobioreactor made of LDPE has light
transmittance lower than the photobioreactor made of PET+CPP as
translucent materials, but light transmittance of each reactor was
measured when 0.33 g/L of Haematococcus pluvialis cell was injected to
two reactors. Then, it was believed that two reactors have the similar
light transmittance from each other.

Example 2

[0090] Measure of Cell Culture in Accordance with Photobioreactor

[0091] A NIES medium (NIES-C) was added to a reactor which has a material
(PET+CPP), a height, a width length, and a side surface length which are
the same as the photobioreactor manufactured in Example 1 except that a
groove in the "V" shape is not formed in the lower portion of the
reactor, and the reactor manufactured in Example 1, Haematococcus
pluvialis (NIES-144) were inoculated, followed by culturing for 2 days
under the same conditions, and then the state of the cells was observed.
A result was shown in Table 1.

[0092] As shown in Table 1, when a groove in the "V" shape was formed in a
lower portion of the photobioreactor, followed by sparging with a small
amount of carbon dioxide mixed gas, the photobioreactor was stirred
homogeneously without aggregation of cells. However, when the
photobioreactor of which the lower portion is flat was sparged with a
small amount of carbon dioxide, it could be confirmed that cells were
aggregated. Therefore, when the photobioreactor is used of which a groove
in the "V" shape is formed in the lower portion, the feed rate of carbon
dioxide may be reduced, and thus microalgae can be cultured economically.

Example 3

[0093] Analysis of Produced Astaxanthin from Haematococcus Pluvialis

[0094] Haematococcus pluvialis (NIES-144) and a NIES-C medium of Table 2
were added to the photobioreactor (made of LDPE) manufactured in Example
1 and a cylindrical photobioreactor (KBT, including a stirrer) made of
glass, followed by culturing. Then, an initial inoculation density was
10% by volume, a culture temperature was 23 to 25, pH was 7.5, a light
intensity was 80 μmol photon m-2s-1, a light period was 24
L:0 D, and a feed rate of carbon dioxide was 20 mL/min. The amount of
astaxanthin extracted from Haematococcus pluvialis was measured in
accordance with culture time. A result was shown in FIG. 9.

[0095] As shown in FIG. 9, when Haematococcus pluvialis were cultured in
the photobioreactor made of LDPE, it was confirmed that the
photobioreactor made of LDPE produces astaxanthin more than that of a
cylindrical photobioreactor made of glass.

[0098] Haematococcus pluvialis (NIES-144) and a NIES-C medium of Table 2
were added to the manufactured photobioreactor (made of LDPE) and a
photobioreactor (made of LDPE) which is the same as described above
except that a partial partition was not formed, followed by culturing.
Then, an initial inoculation density was 10% by volume, a culture
temperature was 23 to 25, pH was 7.5, a light intensity was 80 μmol
photon m-2s-1, a light period was 24 L:0 D, and a feed rate of
carbon dioxide was 20 mL/min. The culture was carried out by changing a
diameter of a sprayer for feeding the carbon dioxide and a feed rate of
carbon dioxide so as to culture actively in the reactor, and then light
transmittance was measured. Therefore, a result was shown in Table 3.

TABLE-US-00003
TABLE 3
Partially Reactor in which the
partitioned inner space is not
reactor partially partitioned
Carbon dixodie Sprayer diameter Including hole in a
sprayer (1.2 cm) pipe having a length
of 15 cm or more, so
as to reach 80% of a
width length of
reactor
Feed rate of about 0.2 VVM 0.5 VVM or more
carbon dioxide
for homogeneous
stirring
Light good (side surface bad (side surface
transmittance length of 2~10 cm) length of 15 cm or
(depth of more)
reactor)

[0099] As shown in Table 3, even though a carbon dioxide sprayer having a
small diameter is used in a partially partitioned reactor and a feed rate
of carbon dioxide is about 0.2 VVM, Haematococcus pluvialis is stirred
and cultured actively. Also, since the reactor is partially partitioned,
the depth thereof is not increased, and therefore light transmittance is
good. Whereas, in the case of the reactor which is not partially
partitioned, the reactor includes a hole in a pipe having a length of 15
to 36 cm, so as to reach 80% of a width length, and thus it could be
confirmed that, when 0.5 VVM or more carbon dioxide is injected,
Haematococcus pluvialis is stirred. In addition, when culture solution is
injected into the reactor which is not partially partitioned, it could be
confirmed that a depth thereof is increased significantly and light
transmittance is degraded.

[0101] Chlorella vulgaris (AG10034) and TAP-C medium (medium removing a
carbon source from TAP medium) with the composition of Table 4 were
injected into the manufactured photobioreactor, followed by culturing. A
result was shown in FIG. 10. Then, an initial inoculation density was 10%
by volume, a culture temperature was 23, pH was 7.0, a light intensity
was 0˜300 μmol photon m-2s-1, a light period was 11
L:13 D (i.e., natural sunlight due to outdoor culture), and a feed rate
of carbon dioxide was 0.1 VVM. A control cultured chlorella in the same
condition except that the photobioreactor was changed to 250 mL of an
Erlenmeyer flask.

[0102] As shown in FIG. 10, it could be confirmed that the amount of
chlorella cultured in a partially partitioned photobioreactor is
increased continuously until 14 days, and the amount of chlorophyll
extracted from chlorella is increased, whereas the amount of cultured
chlorella and chlorophyll in the Erlenmeyer flask is increased gradually
until 8 days, and then is decreased.

[0103] Measure of Light Transmittance in Accordance with Depth of
Photobioreactor

[0104] Haematococcus pluvialis were cultured in the same method except
that the depth of the photobioreactor manufactured in Example 4-1 was
changed. A result was shown in FIG. 11.

[0105] As shown in FIG. 11, it could be confirmed that, when the light of
the certain intensity is transmitted to the reactor, a depth thereof is
increased and light transmittance is decreased.

Experimental Example 2

[0106] Measure of Light Transmittance of Photobioreactor in Accordance
with Materials

[0107] Haematococcus pluvialis (NIES-144) and a NIES-C medium were added
to the photobioreactor (made of LDPE) manufactured in Example 4-1 and a
cylindrical photobioreactor (KBT, including a stirrer) made of glass,
followed by culturing. During the culture, an initial inoculation density
was 10% by volume, a culture temperature was 23 to 25, pH was 7.5, a
light intensity was 80 μmol photon m-2s-1, a light period
was 24 L:0 D, and feed rate of carbon dioxide was 20 mL/min. During the
culture, distance in accordance with a light flux of the same intensity
(258 and 360 μmol photon m-2s-1) was measured, respectively.
A result was shown in FIG. 12.

[0108] As shown in FIG. 12, it was confirmed that the photobioreactor made
of LDPE has the same light transmittance as that of a photobioreactor
made of glass.

[0112] As shown in Table 5, it could be confirmed that the reactor is
stirred homogenously without cell aggregation by using 0.3 to 0.35 VVM of
carbon dioxide in the reactor having a partition interval of 10 cm; the
reactor is stirred homogenously without cell aggregation by using 0.35 to
0.45 VVM of carbon dioxide in the reactor having a partition interval of
15 cm. On the other hands, since the reactor is not stirred homogenously
even using 0.1 to 0.45 VVM of carbon dioxide in the reactor having a
partition interval of 25 cm, 0.5 VVM or more carbon dioxide should be fed
for homogeneous stirring. However, at the time of feeding 0.5 VVM or more
carbon dioxide, carbon dioxide of which the amount is more than the
amount required for the growth of organisms is supplied, buffer is
required for preventing a change in pH of a medium, and the amount of
carbon dioxide to be discharged uselessly may be increased.

[0113] The experiment is carried out by using a sprayer having a diameter
of 1.2 cm. Even though a sprayer with a larger diameter is used and a
partition interval is increased, it is expected that the reactor is
stirred homogeneously by bubble from the sprayer.

[0114] The present invention was described in detail with respect to the
specific portion, but it is only a preferable embodiment in those skilled
in the art and does not limit the scope of the present invention.
Therefore, the substantial range of the present invention is defined by
the accompanying claims and equivalent thereof.

Patent applications by Sang Jun Sim, Seoul KR

Patent applications by Sungkyunkwan University Foundation for Corporate Collaboration

Patent applications in class Including means to transmit light into a bioreactor to facilitate photo- bioreaction (e.g., photosynthesis)

Patent applications in all subclasses Including means to transmit light into a bioreactor to facilitate photo- bioreaction (e.g., photosynthesis)